Fix esbuild charset and target for Netlify compatibility

Set esbuild charset to utf8 and target to es2022 to avoid
syntax errors from ASCII-escaped unicode in the bundled output
on Netlify's build environment.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

astro.config.mjs

@@ -24,5 +24,13 @@ export default defineConfig({
 
   vite: {
     plugins: [tailwindcss()],
+    build: {
+      target: "es2022",
+      minify: "esbuild",
+    },
+    esbuild: {
+      target: "es2022",
+      charset: "utf8",
+    },
   },
 });